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Background: Insulin-like growth factor (IGF)-1 is a peptide hormone implicated in insulin sensitivity and anti-inflammatory. However, there is limited exploration of the association of serum IGF-1 levels with cognitive function and atherosclerosis. This study aimed to investigate the association between serum IGF-1 levels and cognitive function, as well as carotid atherosclerosis in a general population. Methods: In 1,345 participants (544 men; mean age, 68.7 (11.3) years) recruited from the Tanushimaru cohort, we measured their serum IGF-1 levels and evaluated cognitive function using mini-mental state examination (MMSE) and atherosclerosis through carotid intima-media thickness (IMT). Linear regression models were utilized to analyze the association between quartiles of serum IGF-1 levels and MMSE scores, as well as IMT, continuous dependent variables. We also visualized the continuous associations using restricted cubic spline models. Two-sided statistical significance was defined as p <0.05. All statistical analyses were performed using the SAS system (Release 9.4, SAS Institute, Cary, NC, USA). Results: The mean serum IGF-1 level was 96.6 (30.2) ng/ml. Multiple linear regression analysis revealed that the highest quartile of serum IGF-1 levels showed a statistically significant association with higher MMSE scores (p=0.0019), and the third quartile also reached statistical significance (p=0.0006) compared to the lowest. We observed a positive association between serum IGF-1 levels and MMSE scores, even when exploring the full spectrum of serum IGF-1 levels with their spline terms (Figure). In contrast, serum IGF-1 levels did not exhibit a significant association with IMT measurements. Conclusion: High serum IGF-1 levels were associated with higher cognitive function, while no significant association was observed with carotid atherosclerosis. Our findings suggest that IGF-1 levels may play a role in preserving cognitive function, potentially distinct from its role in atherosclerosis.
Nohara‐Shitama et al. (Tue,) studied this question.